Copper Fungicide safe for houseplants?

liz-usaNovember 14, 2012

Hi,

I have a dwarf meyer lemon tree in desperate need of fungicide. I bought Southern Ag's Liquid Copper Fungicide, and I plan on using it soon. However, reading more about heavy metals has made me anxious.

Is Copper Fungicide safe to use on houseplants? This tree sits right behind my couch, where I will undoubtedly inhale anything on the tree.

I was planning on taking it outside to spray. I can maybe leave it in our apartment lobby (outside is near freezing) if it needs to stay outside the apartment, or I can leave it in our basement. Could I spray it, let the fungicide sit, and then wash it off? How long would it need to sit there to kill the fungus killing my tree?

first.. should we defer to your diagnosis.. w/o question??? .. do you need confirmation?? .. i hope you arent winging it based on some online pix ....

second.. what does the label say ... they are .. frankly speaking .. legal documents ... and if insufficient.. they all list phone numbers on them ... all MSDS sheets are provided online ...

i probably would NOT do it .. and i know rhiz wouldnt ... but she usually has alternative options ....

in these cases.. my first thought is usually the overall health of the tree.. as in.. how big it is.. how small is the pot.. and when was the last time it was repotted into fresh media ... most plants that suffer malady... are already so stressed.. that fixing the overtly apparent problems.. usually doesnt rescue the plant ...

BTW .. was it outdoors all summer.. and what is its current light situation.. behind your couch??? ..

My diagnosis is due to the post I put in the citrus forum. I attached the link below.

Do you agree with the diagnosis? Maybe I'm rushing things.... I just get nervous sitting in my apartment, watching my tree lose leaves everyday and not growing any back.

Most greasy spot pics I've seen have yellow spots on green leaves. I have green spots on yellow leaves. I now know that it is not mites, which is what I thought for the last month.

From the pictures, you can see that it is certainly ailing. The tree is a little over 1.5'. The pot is 7" in diameter. I repotted into 511 last night, so I got a good look at the root ball. It is at most 1/3 the size of the pot, which is about how big it was when I bought it.

I've only had it for a month, before which it was at a nursery. I live in cold Massachusetts, in a teeny apartment with no outside space, so it needs to stay inside.

Light situation: it's right in my southeastern window. But, since we're so far North, I also have a grow light 6" above it.

A fungicide has no effect against mites - why would you think this is an appropriate treatment?? Fungicides are for fungal problems. What you need is an insecticide/miticide or something that targets indoor houseplant pests like spider or rust mites, aphids, scale, etc. I'd look at something like Neem oil - not only is it considered an organic control, it is both a miticide, an insecticide AND a moderately effective fungicide - all you could ever need for most houseplant issues.

I agree with the assessment that mites may be causing this damage - they are hugely common on citrus grown indoors - but also agree that a better quality potting soil would be very beneficial as well. Soil should remain evenly moist or just moist to the touch - not wet, not soggy. MiracleGro potting soil tends to be far too moisture retentive and soggy. And do not allow the container to stand in water.

I thought for the longest time that the problem was rust mites, since I thought my lemon had shark skin (still not sure what it was...) But, hoosierquilt pointed out that I'd be able to see them. I haven't seen a single mite, and I've been looking for about a month.

I've switched to a 5-1-1 mix, a bit hastily put together. Still not sure if the orchid bark I got was too coarse. That was a week ago, and I think I'm seeing slow signs of progress. There are little growths on my tree that might be leaves and/or branches, hopefully not more buds.

I think that I've been inadvertently suffocating my tree's roots, so I'm going to try to see how the tree progresses before I use a serious fungicide. As a short-term solution, I wiped down the leaves with hydrogen peroxide, and I haven't seen the fungus spread or grow at all.

hoosierquilt is not correct - citrus mites (and there are several species) are just a form of spider mite common to citrus. They are microscopic - most sources indicate magnification is required to see them as they are about .15mm in length, immature forms even smaller. Dunno what he/her was seeing but it wasn't mites!

Stippling of the foliage is the typical damage, caused by the sucking out of the plant juices, although some mite species can damage the fruits' appearance as well. Not all mite species will produce webbing but that is what you might see - not the creatures themselves.

Growing citrus indoors is not an easy task :-) They dislike the low light, overly dry conditions and often high heat of an indoor setting. There is a strong tendency to overwater to compensate for this and that just creates more problems, especially with a not very good quality potting mix, like the MG. I'm sure repotting with a less dense, less moisture retentive soil will help. And I'd try misting often to bump up humidity. A glass of water in close proximity will help also or standing the pot in a saucer of pebbles with a small amount of water. This is the easiest method to keep mites at bay.

Just be on the look out for other insect pests, which are all too common with indoor citrus (as mentioned). Citrus also tend to be heavy feeders, so fertilize routinely. I would use MG's Miracid (3-1-1 ratio) or FoliagePro by Dyna Gro (3-1-2 ratio) -- the nitrogen component (first number) should be the highest.

Nutrient deficiencies and improper watering/drainage are more likely to be the cause of your foliage problems than insects or any fungal issues. The most important notion I can leave you with is not to make assumptions on what the problems might be and start spraying. Even attempting an online photo diagnosis is tricky at best. Take the plant (or samples of the issues) into a local nursery that specializes in houseplants or to your local extension service for an accurate diagnosis. They can also recommend an appropriate treatment. But don't start spraying a fungicide until you are sure you have a fungal issue. That can often do more harm than good.